Drift indicator knob vibration limiting means



Sept. 2, 1969 Filed May 23, 1966 R. L. ALDER DRIFT INDICATOR KNOB VIBHATION u@ um wvmgmm lm i* LIMITING MEANS 5 Sheets-Sheet l Sept. 2, 1969 R L, ,M DERA 3,464,120

DRIFT INDICATOR KNOB VIHIIA'HON LIMI'IING MEANS Filed May 23, 1966 l 3 SheetQ-Sheet DRIFT INDICATOR KNOB VIBRATION LIMITING MEANS Filed May 25. 1966 R. L. ALDER Sept. 2, 1969 3 Sheets-Sheet 5 United States Patent 3,464,120 DRIFT IDICATOR KNOB VIBRATION LIMITING MEANS Robert Lee Alder, Pasadena, Calif., assignor to Byron Jackson Inc., Long Beach, Calif., a corporation of Delaware Filed May 23, 1966, Ser. No. 552,150 Int. Cl. E211: 47/02 U.S. Cl. 33-205 10 Claims ABSTRACT 0F THE DISCLOSURE A signalling drift indicator of the type in which a knob moves through pulse rings to produce pressure signals in a stream of drilling uid indicative of the disposition of the drill string and in which longitudinally extended ribs are provided between the pulse rings for limiting lateral vibration of the shaft which supports the knob.

The present invention relates to improvements in signalling drift indicators or inclinometers employed to produce signals generated at a location adjacent a well drilling bit indicative of inclination or deviation of the drill bit from the desired drilling disposition, such signals beng transmitted to the earths surface to enable the driller to take such action as may be necessary or desirable to correct the progress of the drill string or maintain the same at the desired inclination, while also enabling the driller to lmaintain substantially a maximum permissible rate of penetration of the earth formation.

Examples of such inclinometers are described and shown in U.S. Letters Patents Nos. 2,435,934 granted Feb. 10, 1948 to Varney et al.; 2,762,132 granted Sept. ll, 1956 to I. A. Varney; and 3,176,407 granted Apr. 6, 19615 to Alder et al.

More particularly, the present invention involves means for enhancing the operation of such inclinometers by reducing substantially the need for maintenance and repair of the subsurface signal producing instrument.

Signal producing instruments of the type here involved include a plunger or knob which is caused by drilling liuid ow to traverse a series of restrictions whereby to produce pressure pulses or signals in the uid stream, either liquid or gaseous drilling fluids, which signals travel in the drilling iluid to the earths surface to actuate pressure pulse responsive indicating or recording instrumentalities, the number of signals being either directly or indirectly representative of angular deviation or drift of the drill bit from vertical.

The pressure knob in such devices is supported on an elongated shaft or stem which is spring loaded upwardly so that when the circulation of drilling uid is halted, the knob will be moved upwardly through the aforementioned restrictions, and when drilling uid circulations is resumed, the knob and shaft are forced downwardly through the restrictions to produce at each restriction a pressure pulse. In order to retard such downward movement of the knob, liquid within the instrument body is caused to pass through means providing essentially a dashpot action whereby the drilling fluid pulses will be of sufficient duration and a frequency suiciently spaced by spacing of the restrictions as to facilitate their being distinguished from normal pump surges or pulses.

Depending upon the extent to which the knob and shaft move upwardly, the shaft on which the knob is disposed projects from the instrument body and is free to vibrate and Hex laterally. Observation of test instruments has shown that such vibration results in damage to the stem, including cracking of the plating on the shaft,

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Wearing of rings on the shaft, and in some instances fatigue failure of the shaft has occurred.

Accordingly, an object of the present invention is to provide a structure in which lateral vibration of the shaft is prevented, thus eliminating the problems attending shaft damage. In this connection, damage to the shaft such as surface cracking and irregular wearing of the shaft results in loss of the seal between the shaft and the housing of the instrument, allowing loss of internal liquid or passage of gas into the housing or the passage of dirty iiuid into the housing, any and all of which results require service of the tool.

In accomplishing the foregoing objective, means are provided on the knob or between the spaced restrictions through which the knob passes for preventing lateral vibration of the knob, thereby stabilizing the shaft, such means being in the form of ribs on the knob engagea'ble in the restrictions while the knob is between restrictions, or ribs between the restrictions engageable with the knob.

In addition to the foregoing, the knob will be prevented from engaging or hanging in a restriction during upward travel of the knob, which would cause a faulty indication of angle when the knob is forced down through the restrictions upon resumption of circulation of drilling uid.

Other objects and advantages of the invention may lbe recognized from the following detailed description, and the novel features of the invention will be defined in the appended claims.

In the drawings:

FIG. 1 is a view partly in elevation, with parts broken away, showing an inclinometer made in accordance with the invention installed in a drill string;

FIG. 2 is an enlarged detail view partly in vertical section and partly in elevation, showing the knob in a partly extended position and located between restrictions;

FIG. 3 is a transverse sectional View, as taken on the line 3 3 of FIG. 2;

FIG. 4 is a fragmentary, longitudinal, sectional View as taken on the line 4 4 of FIG. 2;

FIG. 5 is a view corresponding to FIG. 2, but showing another species of the invention; and

FIG. 6 is a transverse sectional view as taken on the line 6-6 of FIG. 5.

Like reference characters in the several views of the drawings and in the following specification designate corresponding parts.

Referring to FIG. l, the tool or instrument I of the invention is shown as generally comprising an elongated housing 2 adapted to be disposed in a sub or length of drill collar 3 having a threaded pin end 4 and a threaded box 5 at the other end whereby the sub may be installed in a drill string adjacent a bit (not shown) which would preferably be threaded into the box 5.

This instrument comprises, generally, an upper pulse ring section 6, an intermediate pendulum section 7, and a uid reservoir lower section 8. Projectable from the upper end of housing 2 is a generally conical knob 9 which is suitably mounted upon the upper end of a reciprocable shaft 10. A spring 11 within the housing 2 abuts with a flange 12 on shaft 10` and with a lower shoulder 13 for normally biasing the shaft upwardly. Means responsive to deviation from vertical, namely a pendulum 14, and a plurality of axially spaced stop ridges 15 are provided for limiting spring biased upward movement of the shaft 10 in accordance wtih the angular disposition of the drill collar 3 and hence the instrument I.

Thus, the stop ridges are of progressively smaller diameter from bottom to top and are spaced axially, while the pendulum 14 is pivotally universally connected as at 16 to the lower end of shaft 10 and is provided with a shoulder 17 adapted to engage one of the ridges 15 upon upward movement of shaft 10 if the instrument I is not disposed vertically, as a result of which gravity will cause the pendulum to be disposed angularly relative to the housing 2 for abutting engagement with a ridge 15.

The instrument I is coaxial with the drill collar 3 and is mounted therein by means of a bottom support 18 which bottoms at 19 on a shoulder at the lower end of the drill collar and is threaded as at 20 into the bottom of housing 2. This bottom support is in the nature of an annular collar connected by spaced webs 20a to a hub 21 having an opening 22 therein. At its upper end the housing 2 is preferably removably connected to the pulse ring section 6 by means of a spider 23 which provides flow passageways 24 between the housing 2 and a supporting sleeve or skirt 25 of the pulse ring section. At its upper end the pulse ring section shoulders at 26 with the drill collar 3, and sealing means 27 are provided externally of the pulse ring section.

As previously described, the instrument is employed as drilling nid is being pumped from the earths surface through the drill collar 3. It will now be understood that the fluid will impinge upon the knob 9 and force the knob and shaft downward against the bias of spring 11 until the head is, as shown in FIG. 1, fully down. Under such conditions, the pendulum 14 is adapted to engage in a pendulum seat 29 formed as a part of flow restricting and by-pass assembly 30. This assembly comprises a body 31 suitably mounted in the housing 2 of the instrument and having a bore 32 therein. Mounted in the bore is a series of orifice discs 33. Pendulum seat 29 is ported at 34 and a retainer plug 35 for discs 33 is ported at 36. Below the body 31 is suitable divider means illustrated herein as a diaphragm 37. The housing 2 is filled with clean liquid which will be pressurized by the fluid outside the housing 2. In order to allow relatively free passage of fluid in the housing 2 from below the body 31 to the housing above said body 31, the latter is provided with a check valve 38 in a passage 39 which opens upwardly but closes downwardly to cause the diversion of all fluid in the housing 2 to a ow path through the orifice discs 33 upon downward flow of uid through body 31.

Since the internal fluid fills housing 2, upward movement of knob 9 and shaft 10 will cause the transfer of fluid upwardly through the passage 39 and check valve 38, and downward movement of the knob and shaft will cause the iiuid to pass through orifice discs 33, the orces of which restrict ow so as to retard such downward movement. At the upper end of the housing 2, sealing means are provided about the shaft 10. In the illustrative embodiment, such sealing means is shown as an O-ring 40 disposed in a groove in a flange 41 through which the shaft extends.

Within the pulse ring section above skirt 25 is a series of annular flanges or pulse rings 42 forming annular restrictions only slightly larger than the diameter of the knob 9 on shaft 10. These pulse rings are axially spaced a distance related to the distance between pendulum stop ridges 15, whereby upon cessation of the circulation of drilling uid and depending upon the angular disposition of the instrument, upward movement of the shaft 10 will be limited so as to position the knob between adjacent pulse rings. When circulation of drilling Huid is again resumed, the knob 9 will momentarily block fiuid flow as it passes through the pulse rings causing the production of a pressure pulse or signal in the column of drilling fluid, which signal will travel through the fluid column to the earths surface for detection or recordation as an indication of inclination of the drill collar 3.

In'asmuch as the shaft 10 projects a specific distance past the seal 40 and flange 41 at the upper end of the housing 2 in relation to each angular position, as determined by the pendulums engagement with the stop ridges 15, and inasmuch as downward movement of the shaft is retarded as described above, the free end of the shaft is free to vibrate or whip violently due to the forceful '4 ow of drilling fluid therepast. It has been observed that damage has occurred to the shaft as a result of such vibration.

In this connection, it has been discovered that shafts have worn locally in rings or bands in axially spaced regions of the shaft which are disposed in the closely fitting flange 41 and seal 40 at the top of housing 2, such bands being spaced correspondingly to the space between the pulse rings 42. Such wear was attributable to vibration or whipping of the shaft. In addition, shafts which have been plated have evidenced plating damage, cracking and peeling attributable to such vibration. Indeed shafts have broken due to fatigue attributable to such vibration.

In accordance with the present invention, means are provided which cooperate between the knob and the pulse ring sleeve to limit lateral movement of the knob when it is disposed in the axial spaces between the pulse rings.

As seen in FIGS. l-4, the invention contemplates the provision of rib means spanning the space between pulse rings, such rib means comprising angularly spaced ribs 43 extended axially and projecting inwardly substantially to the periphery of the pulse rings. In this illustrative embodiment there are six equdistantly spaced ribs 43 between adjacent pulse rings, leaving therebetween pockets 44 which afford substantial flow area for the passage of drilling fluid past the knob while it is between pulse rings, as shown in FIG. 2, but minimizing clearance between ribs 43 and knob 9 so as to limit vibration or whipping of the shaft.

In FIGS. 5 and 6 there is shown another embodiment of means for limiting vibration of the shaft 10. In this embodiment, the pulse ring section 6 is, as in FIGS. 1-4, provided with axially spaced pulse rings 42, but whereas in FIGS. 1-4 ribs 43 are disposed between the pulse rings, FIGS. 5 and 6 show -ribs 43a provided on the knob 9.

These ribs 43a are longitudinally extended so as to span three of the pulse rings. At their lower outer extremity the ribs 43a are bevelled at 43b and at their upper outer extremity they are bevelled at 43C s0 as to avoid hanging on the pulse rings during either upward or downward movement of the knob through the pulse rings.

In FIGS. 5 and 6 the knob is shown as having three equdistantly spaced ribs 43a ,and the knob is also shown as having a like number of angularly spaced marginal openings 9a affording passageways for large particles of earth or stone which may be entrained in the drilling fluid. It will be understood that if desired the knob 9 of FIGS. 1-4 may likewise be provided with marginal openings such as the openings 9a.

Iclaim:

1. A signalling apparatus adapted to be installed in a well drilling string for producing pressure signals in a stream of well drilling fluid indicative of the angular disposition of the drill string from the desired drilling disposition, said apparatus comprising: an elongated housing, a shaft having a free end projecting from said housing and its other end disposed in said housing; means in said housing for biasing said shaft to move in one direction, gravity responsive means, for limiting such movement of said shaft, said free end of said shaft providing a surface exposed to the drilling fluid stream, said stream causing said shaft to move in the other direction against said biasing means, pulse ring means in the path of the fluid stream cooperative with said free end providing a number of spaced restrictions through which said free end passes during movement of said free end, and rib means cooperable between said pulse ring means and said free end of said shaft for limiting lateral vibration of said free end.

2. A signalling apparatus as defined in claim 1, wherein rib means for limiting lateral vibration of said free end comprise angularly spaced ri-bs on said pulse ringv means disposed in the spaces between said restrictions.

3. Signalling apparatus as defined in claim 1, wherein said free end of said shaft has an enlarged knob thereon and said pulse ring means comprises a tubular member in which said knob is reciprocable, said tubular member having annular rings forming said restrictions.

4. A signalling apparatus as defined in claim 3, wherein said rib means for limiting vibration of said free end comprises angularly spaced ribs between said rings.

5. Signalling apparatus as defined in claim 3, wherein said rib means for limiting vibration of said free end comprises angularly spaced ribs on said knob extending lengthwise for engagement with said rings.

6. Signalling apparatus as defined in claim 3, wherein said knob is provided with angularly spaced peripheral openings for passage of large particles.

7. Signalling apparatus as defined in claim 1, wherein said housing is lled with liquid, and including seal means between said housing and said shaft, shiftable divider means for balancing the pressure in said housing with the external pressure as said shaft moves in said one direction, and fluid ow impedng means in said housing for retarding movement of said shaft in the other direction.

8. Signalling apparatus as dened in claim 1, wherein said pulse ring means comprises a tubular member having axially spaced annula-r ridges therein forming said restrictions, and said rib means comprises a plurality of angularly spaced ribs on said shaft spanning a number of said ridges and having bevelled outer end extremities for preventing hanging of said ribs on said ridges.

9. A pulse ring unit for signalling drift indicators, comprising: a tubular body having thereon a plurality of axially spaced annular rings therein and a plurality of angularly spaced ribs disposed between said rings and projecting substantially to the periphery of said rings.

10. A knob for signalling drift indicators comprising: a generally conical knob having an annular outer periphery, and a plurality of angularly spaced ribs extended longitudinally of said knob and having upper and lower extremities projecting from said knob.

References Cited UNITED STATES PATENTS 3,176,407 4/ 1965 Alder etal. 2,762,132 9/1956 Varney. 2,43 5,934 2/ 1948 Varney et al.

LEONARD FORMAN, Primary Examiner F. J. DAMBROSIO, Assistant Examiner U.S. Cl. X.R. -45 

